نتایج جستجو برای: production diversification

تعداد نتایج: 623133  

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2005
Birgitte Freiesleben De Blasio Fabio Vittorio De Blasio

We present a simple model of adaptive radiation in evolution based on species competition. Competition is found to promote species divergence and branching, and to dampen the net species production. In the model simulations, high taxonomic diversification and branching take place during the beginning of the radiation. The results show striking similarities with empirical data and highlight the ...

Journal: : 2022

This paper deals with the possibilities and challenges through impact of using improved seeds technologies on crop production particularly in case eastern hilly area Nepal. The study applied househod questionnaire survey, key informant survey field observation to collect relevant information. conducted 30 percent (180hss) total (601hhs) three altitude belts such as upper, middle lower, ranging ...

2011
Tiago B. Quental Charles R. Marshall

Molecular phylogenies have been used to study the diversification of many clades. However, current methods for inferring diversification dynamics from molecular phylogenies ignore the possibility that clades may be decreasing in diversity, despite the fact that the fossil record shows this to be the case for many groups. Here we investigate the molecular phylogenetic signature of decreasing div...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران - دانشکده علوم 1370

تهیه ترکیب فسفرتری کلرید بااستفاده از واکنش فسفر سفید(زرد) و گاز کلر در فاز محلول و درمقیاس آزمایشگاهی موردمطالعه قرارگرفت .پس از انتخاب مناسبتر روش و انتخاب بهترین شرایط کوشش درجهت طراحی واحد نیمه صنعتی انجام شد و توانستیم دراین راستا به تولید 10 کیلوگرم درساعت باخلوص 99/5 درصد برسیم . abstract the preparation of phosphorous trichloride by the reaction of white phosphorous and chlorine gas in ...

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